Composite structure diagram
Composite structure diagrams show the internal structure of a class and the relationships of the individual class components to one another.
The image above extends the example from Figure 2 with an additional class involved in an order, the invoice. Unlike the order item, the invoice is not a compositional component of an order but is directly assigned to it. The invoice also refers to the individual order items.
The Composite structure diagram in Figure 9 provides an alternative representation to the Class diagram in Figure 8. The two attributes invoice and itemline are represented graphically in the Order class as symbols of the Property or Part type. The dotted border of the invoice property symbol indicates that the invoice is not a compositional component of the order, while the solid border of the itemline part symbol means that order items are included in the composition of the order.
The two symbols are linked by a connector with the name p, which refers to the Invoice line item association shown in Figure 8.